Week 10

Question 1

Strong Entity

Answer 1

Has it’s own unique identifier

Question 2

Weak Entity

Answer 2

Does not have its own unique identifier, inherits it from its supporting entity

Question 3

Participation Constraints

Answer 3

For Has-A relationships
Total participation (existence dependency) – an entity can only exist if it participates in a specific relationship (weak entities always)
Partial Participation – an entity can exist without participating in relationship

Question 4

Identifying vs non-identifying relationships

Answer 4

identifying – solid line that denotes that the foreign key will help form a PK
Non-identifying – dashed relationship that the foreign key will not be needed to form a primary key

Question 5

Associative Entity

Answer 5

a term used in relational and entity–relationship theory to represent a mutual relationship between two entities, also known as a many-to-many relationship.